The present invention relates to edible microporous materials, and more specifically, to a method for the manufacture of a microporous, inorganic, essentially non-hygroscopic, cation-sugar salt which is capable of adsorbing large volumes of diverse flavor and aroma components or gases, such as carbon dioxide.
In the area of prepared foods, there is a basic need to offer a packaged food or drink product, that is attractive to the various senses of the mature consumer. With the purchase of the product, the first barrier is overcome. Opening the container or jar is usually the next preparatory step that the consumer undertakes. The packaging and retention of food products within a closed container presents unique problems to the manufacturer. Greeting the consumer's olfactory senses is the "headspace" aroma, said aroma comprising volatile components which hang suspended in the void between the jar cap and the dried mix. Upon receiving the aroma via olfactory receptors, the consumer arrives at a perception of whether or not the product contained therein is fresh and potentially attractive to the taste. In fact, freshness and taste quality may not consistently be ascertained in this manner. Therefore, it is imperative that an intensely pleasant yet familiar aroma wafts up to the consumers' olfactory senses, regardless of the length of time that the product has endured storage. After a portion has been extracted from the container or jar, the container is resealed, only to be reopened for a second test of product acceptability. When the consumer opens the container for the second time, he or she expects to be met by the same pleasant and familiar aroma that was perceived in the first instance. Hence, the "headspace aroma", the aroma suspended within the air space beneath the jar cap of a dried food or drink mix, is still of strategic import; if there is no aroma, then there is a supposition that the product has become stale. Such a misperception often militates against the repurchase of the product by the consumer. The desired presence of a headspace aroma with each successive opening of the jar, commonly referred to as an in-use headspace aroma, can only exist if the aroma source does not release all sorbed aroma at one time.
A second expected quality of dried food or drink mixes is that said mixes provide a well rounded flavor when reconstituted with water. Often the process of preparing the dried product removes the deeper tones from the comestible, making the product organoleptically unsatisfactory. Moreover, it is often difficult to load the dried mix with flavor components, since these components are often volatile and are lost when the container is repeatedly opened. Again, as with aroma, the consumer is stereotypically fixated on certain flavors that have become familiar to him or her. And again, if the expectation of experiencing the characteristic flavor is not realized by the consumer, negative feelings will accrue with adverse effects upon the continued purchase of the product. Therefore, there has been a long standing need for an easily added edible carrier that can actively adsorb large quantities of volatile flavor and aroma components so that said components can be releasibly held, so that when the product is reconstituted or when the container is opened said components will be liberated via controlled release.
The use of edible "microporous" material as sorbents for gases and aromatic volatile has been disclosed in U.S. Pat. No. 4,389,422 to Hudak and a related patent disclosures such as Canadian Pat. No. 1,142,018 to Hudak and Saleeb. The fomation of "microporous" sucrose particles has been disclosed in filed U.S. patent application, Ser. No. 375,052 filed May 5, 1982. These sucrose particles have, however, been found to be hygroscopic and to quickly loose porosity upon exposure to the atmosphere.
Microporous or highly porous sorbents possess a relatively large surface area in excess of ten square meters per gram and also possess a large number of pores within the range of 10 to 20 angstroms in radius. These particles rely on their internal pore structure to provide such large surface areas as, by way of illustration, cubic particles of sodium chloride having a side dimension as small as one micron would only provide a geometric or external surface area of 2.8 m.sup.2 /g (reference: Adamson, Physical Chemistry of Surfaces, p. 247, Interscience Publishers, Inc., 1960). Microporous particles will evidence a phenomenon known as capillary condensation in which liquids condense within the 10 to 250 angstrom pores at vapor pressures significantly below saturation.
U.S. Pat. No. 4,263,052 to Bicksel et al. teaches that a "sugar-salt" complex may be formed although the product would not be microporous; the method described therein teaches a method for deriving a crystalline form of fructose of high purity.
U.S. Pat. No. 4,237,147 to Merten et al. teaches a method for forming an amorphous calcium carbonate complex which readily releases carbon dioxide on acid hydrolysis.
Of interest is British Pat. No. 2,071,104 issuing to Koshida et al., said reference teaching the formation of porous saccharide granules. The essentially crystalline composition is macro-porous and the potential constituents exclude such saccharides as fructose or glucose.
Heretofore there has not been a successful attempt to create microporous glucose or fructose sorbents or moisture-stable sucrose sorbents to adsorb gaseous components therein.